CN213877984U

CN213877984U - Circuit breaker

Info

Publication number: CN213877984U
Application number: CN202022997204.0U
Authority: CN
Inventors: 魏首勋
Original assignee: Shenzhen Mantunsci Technology Co ltd
Current assignee: Shenzhen Mantunsci Technology Co ltd
Priority date: 2020-12-14
Filing date: 2020-12-14
Publication date: 2021-08-03
Anticipated expiration: 2030-12-14

Abstract

The utility model provides a circuit breaker. The circuit breaker comprises a shell, a first wiring terminal, a second wiring terminal, a switch assembly and a time delay tripping mechanism, wherein the first wiring terminal, the second wiring terminal, the switch assembly and the time delay tripping mechanism are arranged in the shell; the switch component comprises a moving contact and a fixed contact, and a wiring part is convexly arranged on the moving contact; the wiring part is electrically connected with the delay tripping mechanism through a first lead; the wiring portion is further electrically connected with the second wiring end through a second conducting wire, and the fixed contact is electrically connected with the first wiring end. The utility model discloses a circuit breaker can improve the heat dispersion of circuit breaker, and then improves the reliability of circuit breaker.

Description

Circuit breaker

Technical Field

The utility model relates to the technical field of electrical apparatus, in particular to circuit breaker.

Background

The circuit breaker is a switching device capable of closing, carrying, and opening/closing a current under a normal circuit condition and a current under an abnormal circuit condition within a prescribed time. The circuit breaker is divided into a high-voltage circuit breaker and a low-voltage circuit breaker according to the application range, the boundary of the high voltage and the low voltage is divided more clearly, the circuit breaker is generally called as a high-voltage electrical appliance with the voltage of more than 3kV, the circuit breaker can be used for distributing electric energy, an asynchronous motor is not frequently started, a power supply circuit, the motor and the like are protected, when the circuit breaker generates serious faults such as overload, short circuit, undervoltage and the like, the circuit can be automatically cut off, the function of the circuit breaker is equivalent to the combination of a fuse type switch, an over-under-heat relay and the like, and parts are generally not required to be changed after fault current is cut off. The existing circuit breaker is developing towards multi-functionalization and miniaturization, and the problem of poor heat dissipation exists due to the fact that the layout in the circuit breaker is compact, and the circuit breaker is very prone to damage and safety accidents due to the fact that the heat dissipation difference can cause the temperature of the circuit breaker to rise in the operation process.

SUMMERY OF THE UTILITY MODEL

The utility model discloses a main aim at providing a circuit breaker aims at improving the heat dispersion of circuit breaker, and then improves the reliability of circuit breaker.

In order to achieve the above object, the present invention provides a circuit breaker, which includes a housing, and a first terminal, a second terminal, a switch assembly and a delay tripping mechanism disposed in the housing, wherein the first terminal, the switch assembly and the second terminal are electrically connected in sequence to form a main circuit, and the switch assembly is used for controlling on/off of a power supply of the main circuit; the switch component comprises a moving contact and a fixed contact, and a wiring part is convexly arranged on the moving contact; the wiring part is electrically connected with the delay tripping mechanism through a first lead; the wiring portion is further electrically connected with the second wiring end through a second conducting wire, and the fixed contact is electrically connected with the first wiring end.

Optionally, the movable contact is arranged opposite to the fixed contact, the movable contact is movably switched between an opening position and a closing position and is arranged in the housing, a first contact portion is arranged on one side of the movable contact facing the fixed contact, a second contact portion is arranged on the fixed contact corresponding to the first contact portion, and when the movable contact is in the closing position, the first contact portion is abutted to the second contact portion and is in surface contact with the second contact portion.

Optionally, a protrusion is disposed on one side of the moving contact facing the fixed contact, the first contact portion is disposed on the protrusion, an accommodating groove is disposed at a position of the moving contact corresponding to the protrusion, and the protrusion is fixedly mounted in the accommodating groove.

Optionally, the protrusion is fixed in the accommodating groove by welding, a filling welding layer is formed by welding the protrusion and the moving contact, a groove is formed on one side of the moving contact facing the protrusion or one side of the protrusion facing the moving contact, and the groove is used for accommodating the filling welding layer.

Optionally, a plurality of protrusions are arranged on one side of the convex block facing the moving contact, the plurality of protrusions are sequentially arranged at intervals along the length direction of the convex block, and the groove is formed between every two adjacent protrusions.

Optionally, the delay tripping mechanism includes a first metal piece and a second metal piece, the wiring portion is connected to the first metal piece through the first wire, one end of the second metal piece is connected to the first metal piece, and the other end of the second metal piece is connected to the second terminal.

Optionally, the second metal piece includes a plurality of metal plates connected in sequence, and the plurality of metal plates are arranged in a winding and roundabout manner.

Optionally, the bump is made of a silver alloy material; and/or the thickness of the bump is larger than that of the movable contact.

Optionally, the housing is further provided with heat dissipation holes.

Optionally, the circuit breaker further includes an instantaneous trip mechanism and an arc extinguishing mechanism, one end of the instantaneous trip mechanism is electrically connected to the first wiring terminal, the other end of the instantaneous trip mechanism is electrically connected to the fixed contact, one end of the arc extinguishing mechanism is electrically connected to the fixed contact, and the other end of the arc extinguishing mechanism is electrically connected to the delay trip mechanism.

The technical scheme of the utility model, through set up first wiring end, the second wiring end, switch module and time delay tripping device in the casing, first wiring end, switch module and second wiring end electric connection constitute the main loop in proper order, switch module is used for controlling the power on/off of main loop, switch module includes moving contact and static contact, the moving contact epirelief is equipped with wiring portion, wiring portion is through first wire and time delay tripping device electric connection, wiring portion still passes through second wire and second wiring end electric connection, static contact and first wiring end electric connection, protruding wiring portion has increased the volume of moving contact, make the heat radiating area increase of moving contact, thereby make the heat dissipation of moving contact fast; simultaneously, first wire and second wire all are connected with the wiring portion on the moving contact, and for only a wire is connected with the moving contact, first wire and second wire have increased the area of contact with the moving contact for contact resistance between first wire, second lead and the moving contact is little, and the circuit breaker is low at the in-process temperature rise of operation, and the use of circuit breaker is safe and reliable more. Therefore, the utility model discloses a circuit breaker can improve the heat dispersion of circuit breaker, and then improves the reliability of circuit breaker.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.

Fig. 1 is a schematic structural diagram of an embodiment of a circuit breaker according to the present invention;

FIG. 2 is a schematic view of a portion of the structure of FIG. 1;

FIG. 3 is a schematic view of a portion of the structure of FIG. 2;

FIG. 4 is an enlarged view taken at A in FIG. 3;

FIG. 5 is a schematic diagram of the structure of FIG. 3 from another perspective;

fig. 6 is an enlarged view at B in fig. 5.

The reference numbers illustrate:

the purpose of the present invention is to provide a novel and improved method and apparatus for operating a computer.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.

It should be noted that, if directional indications (such as upper, lower, left, right, front and rear … …) are involved in the embodiment of the present invention, the directional indications are only used to explain the relative position relationship between the components, the motion situation, etc. in a specific posture (as shown in the drawings), and if the specific posture is changed, the directional indications are changed accordingly.

In addition, if there is a description relating to "first", "second", etc. in the embodiments of the present invention, the description of "first", "second", etc. is for descriptive purposes only and is not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions in the embodiments may be combined with each other, but it must be based on the realization of those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should not be considered to exist, and is not within the protection scope of the present invention.

The utility model provides a circuit breaker 10.

Referring to fig. 1 to 4, in an embodiment of the circuit breaker 10 of the present invention, the circuit breaker 10 includes a housing 100, and a first terminal 200, a second terminal 300, a switch assembly 400 and a delay trip mechanism 500 disposed in the housing 100, wherein the first terminal 200, the switch assembly 400 and the second terminal 300 are electrically connected in sequence to form a main circuit, and the switch assembly 400 is used for controlling on/off of a power supply of the main circuit; the switch assembly 400 includes a moving contact 410 and a fixed contact 430, wherein a wiring portion 411 is convexly arranged on the moving contact 410; the wiring portion 411 is electrically connected to the delay trip mechanism 500 through a first conductive wire; the wiring portion 411 is further electrically connected to the second terminal 300 through a second conductive wire, and the fixed contact 430 is electrically connected to the first terminal 200.

Specifically, the first terminal 200 may be an input terminal of the circuit breaker 10, and may also be an output terminal of the circuit breaker 10, in this embodiment, the first terminal 200 is taken as an input terminal of the circuit breaker 10 for example, and then the second terminal 300 is taken as an output terminal, and the switch assembly 400 is disposed between the input terminal and the output terminal. The first terminal 200, the switching assembly 400 and the second terminal 300 are electrically connected in sequence to form a main circuit, the switching assembly 400 has an open state and a closed state, and the switching assembly 400 controls power on/off of the main circuit by switching between the open state and the closed state. The switch assembly 400 includes a moving contact 410 and a stationary contact 430, when the switch assembly 400 is in a closed state, the moving contact 410 is in contact with the stationary contact 430, and the current accessed by the first terminal 200 is output to the second terminal 300 through the stationary contact 430 and the moving contact 410 of the switch assembly 400; when the switch assembly 400 is in the open state, the movable contact 410 is separated from the fixed contact 430, so that the first terminal 200 and the second terminal 300 are disconnected. The time delay trip mechanism 500 is used to provide overcurrent protection for the circuit breaker 10, and the time delay trip mechanism 500 is described in more detail below.

Further, the wire connecting portion 411 may be protruded toward the first terminal 200 or the second terminal 300, and the protruding direction is not limited herein. The protruding wiring portion 411 of establishing is used for being connected with the wire, and first wire and second wire can be located same one side of wiring portion 411, also can locate the relative both sides of wiring portion 411, can be equipped with wiring groove or terminal on the wiring portion 411 to make things convenient for the connection of wire to fix. There are various ways to connect and fix the first wire and the second wire, such as but not limited to: the first and second conductive wires may be fixed to the connection portion 411 by welding, or may be locked and fixed to the connection portion 411 by a bolt structure. The protruding wiring portion 411 of establishing has increased the volume of moving contact 410 for moving contact 410, and first wire and second wire all are connected with wiring portion 411 moreover, have increased area of contact between the three, make the contact resistance between the three little like this, and the heat that circuit breaker 10 during operation produced is few, and the temperature rise is low, and circuit breaker 10's use safe and reliable.

The technical scheme of the utility model, through set up first wiring end 200 in casing 100, second wiring end 300, switch module 400 and time delay tripping mechanism 500, first wiring end 200, switch module 400 and second wiring end 300 electric connection constitute the major loop in proper order, switch module 400 is used for controlling the power on/off of major loop, switch module 400 includes moving contact 410 and static contact 430, the epirelief of moving contact 410 is equipped with wiring portion 411, wiring portion 411 is through first wire and time delay tripping mechanism 500 electric connection, wiring portion 411 still is through second wire and second wiring end 300 electric connection, static contact 430 and first wiring end 200 electric connection, protruding wiring portion 411 of establishing has increased the volume of moving contact 410, make the heat radiating area increase of moving contact 410, thereby make the heat dissipation of moving contact 410 fast; meanwhile, the first wire and the second wire are both connected with the wiring part 411 on the movable contact 410, and compared with the situation that only one wire is connected with the movable contact 410, the contact area between the first wire and the movable contact 410 is increased by the first wire and the second wire, so that the contact resistance between the first wire and the movable contact 410 and the second wire and the movable contact 410 is small, the temperature rise of the circuit breaker 10 in the operation process is low, and the circuit breaker 10 is safer and more reliable to use. Therefore, the utility model discloses a circuit breaker 10 can improve circuit breaker 10's heat dispersion, and then improves circuit breaker 10's reliability.

Referring to fig. 2 to 4, in an embodiment, the movable contact 410 and the fixed contact 430 are disposed opposite to each other, the movable contact 410 is disposed in the housing 100 in a switchable manner between an opening position and a closing position, a first contact portion 421 is disposed on a side of the movable contact 410 facing the fixed contact 430, a second contact portion 431 is disposed on the fixed contact 430 corresponding to the first contact portion 421, and when the movable contact 410 is in the closing position, the first contact portion 421 abuts against and is in surface contact with the second contact portion 431.

Specifically, the switch component drives the moving contact 410 to switch between the open position and the close position by rotating, a first contact portion 421 of the moving contact 410 has a first contact surface, a second contact portion 431 of the static contact 430 has a second contact surface, and the first contact surface and the second contact surface may be both planar surfaces, may also be a planar surface, and the other one may be a curved surface, and may also be an arc surface, which is not limited herein. When the moving contact 410 is at the switching-on position, the first contact surface abuts against the second contact surface, so that the moving contact 410 is in good contact with the static contact 430, and compared with the existing contact between the moving contact 410 and the static contact 430 through edge-to-surface contact, the moving contact 410 and the static contact 430 are in surface contact, so that the contact area of the moving contact 410 and the static contact 430 is large, the contact resistance is small, the temperature rise of the breaker 10 in the operation process is low, the heat dissipation is fast, the breaker 10 is safe and reliable in use, and the reliability of the breaker 10 is improved.

Further, a protrusion 420 is disposed on a side of the movable contact 410 facing the fixed contact 430, the first contact portion 421 is disposed on the protrusion 420, a receiving groove is disposed at a position of the movable contact 410 corresponding to the protrusion 420, and the protrusion 420 is fixedly mounted in the receiving groove. It can be understood that the first contact portion 421 is disposed on the protrusion 420, the protrusion 420 is used for abutting against the second contact portion 431 of the static contact 430, the protrusion 420 is disposed to increase the volume of the moving contact 410, which is beneficial to heat dissipation of the moving contact 410, and the protrusion 420 is fixedly mounted in the receiving groove, so that the protrusion 420 is conveniently located. The way in which the protrusion 420 is fixedly installed is various, such as but not limited to: the protrusion 420 is fixed in the receiving groove by welding, or fixed in the receiving groove by a screw connection, or fixed in the receiving groove by a snap connection. The fixed installation of the protrusion 420 in the receiving groove can ensure the stability of the contact between the movable contact 410 and the fixed contact 430, thereby improving the reliability of the circuit breaker 10.

Further, the bump 420 is made of a silver alloy material. The moving contact 410 and the static contact 430 can be made of conductive materials, in this embodiment, the moving contact and the static contact are made of copper materials, the bump 420 is made of silver alloy materials, and the silver alloy materials have the advantages of low resistivity, good conductive performance and no arcing, so that the conductivity of the moving contact 410 can be improved, and heat generated when the moving contact 410 is in contact with the static contact 430 can be reduced. In addition, the thickness of the protrusion 420 is greater than that of the movable contact 410. By the arrangement, the volume of the movable contact 410 is increased, so that the contact area between the movable contact 410 and the fixed contact 430 is larger, the contact resistance between the movable contact and the fixed contact is small, the heat dissipation area is large, and the heat dissipation performance of the circuit breaker 10 is further improved.

Referring to fig. 5 and 6, in an embodiment, the protrusion 420 is fixed in the receiving groove by welding, the protrusion 420 and the movable contact 410 are welded to form a solder filling layer, and a groove is disposed on one side of the movable contact 410 facing the protrusion 420 or one side of the protrusion 420 facing the movable contact 410, and the groove is used for receiving the solder filling layer. It can be understood that, when the protrusion 420 is disposed in the receiving groove of the movable contact 410, a gap is formed between the protrusion 420 and the movable contact 410, the protrusion 420 and the movable contact 410 are fixedly connected by welding, so that the connection between the protrusion and the movable contact is firmer, the movable contact 410 is provided with a groove toward one side of the protrusion 420 or one side of the protrusion 420 toward the movable contact 410, a filling solder layer formed by welding is filled in the groove, so that no gap is formed between the protrusion 420 and the movable contact 410, the connection between the protrusion and the movable contact is tighter, and the side of the protrusion 420 and the movable contact 410 is disposed relative to the filling solder layer, the filling solder layer is disposed on the opposite surface between the protrusion 420 and the movable contact 410, so that the contact area between the protrusion 420 and the movable contact 410 is large, the contact resistance between the protrusion and the movable contact is small, the heat generation amount is small, the temperature rise of the movable contact 410 in the operation process of the circuit breaker 10 is low, and the use of the circuit breaker 10 is safer and more reliable.

Further, one side of the protrusion 420 facing the movable contact 410 is provided with a plurality of protrusions 422, the plurality of protrusions 422 are sequentially arranged at intervals along the length direction of the protrusion 420, and the groove is formed between adjacent protrusions 422. It can be understood that, the protrusion 420 and the movable contact 410 are made of conductive materials, and compared with the processes of machining parts in the receiving groove of the movable contact 410 and machining parts on the protrusion 420, the protrusion 420 has a smaller volume, which is more beneficial to machining, and the groove formed by the adjacent protrusion 422 makes the machining process of the protrusion 420 simpler, thereby improving the manufacturability of the circuit breaker 10.

Further, the housing 100 is provided with heat dissipation holes. The heat generated by the circuit breaker 10 during operation can be discharged from the heat dissipation holes on the housing 100, so as to improve the heat dissipation effect of the circuit breaker 10, avoid the damage and safety accident caused by the over-high temperature inside the housing 100 of the circuit breaker 10, and further improve the reliability of the circuit breaker 10.

Referring to fig. 3 to 6, in an embodiment, the delay trip mechanism 500 includes a first metal piece 510 and a second metal piece 520, the connection portion 411 is connected to the first metal piece 510 through a first conductive wire, one end of the second metal piece 520 is connected to the first metal piece 510, and the other end of the second metal piece 520 is connected to the second terminal 300.

Specifically, the time delay trip mechanism 500 is used for providing overcurrent protection for the circuit breaker 10, two ends of the second metal member 520 may be respectively connected to the first metal member 510 and the second terminal 300 by welding, the first metal member 510 is disposed in a sheet shape and may be bent and deformed due to heat generation under the action of current, the first metal member 510 is connected to the wiring portion 411 of the movable contact 410 of the switch assembly 400 through a first wire, the switch assembly 400 includes a driving member 440, and the driving member 440 drives the switch assembly 400 to close and open through a pull rod 441. When the circuit breaker 10 normally works, the switch assembly 400 is in the on-position, the current output by the switch assembly 400 is transmitted to the second terminal 300 through the first metal piece 510 and the second metal piece 520 of the delay trip mechanism 500, and when the current passing through the first metal piece 510 exceeds a preset value, the first metal piece 510 bends and deforms due to heating, and the pull rod 441 with the driving piece 440 moves, so that the switch assembly 400 is in the off-position, and the overcurrent protection of the circuit breaker 10 is realized. In the process, the second metal part 520 plays a role in conducting electricity, and compared with the situation that the first metal part 510 is directly connected with the second terminal 300, the second metal part 520 increases the heat dissipation area of the delay tripping mechanism 500, so that the current can dissipate heat through the first metal part 510 and the second metal part 520, the heat dissipation area is large, the heat dissipation of the delay tripping mechanism 500 is fast, and the heat dissipation performance of the current breaker is further improved.

Further, the second metal piece 520 includes a plurality of metal plates connected in sequence, and the plurality of metal plates are arranged in a winding and weaving manner. It can be understood that the plurality of metal plates increase the volume of the second metal part 520, so that the heat dissipation area of the second metal part 520 is large, and the heat dissipation is fast when the current passes through the second metal part 520, thereby improving the heat dissipation performance of the delay trip mechanism 500.

Referring to fig. 2, in an embodiment, the circuit breaker 10 further includes an instantaneous trip mechanism 600 and an arc extinguishing mechanism 700, one end of the instantaneous trip mechanism 600 is electrically connected to the first terminal 200, the other end of the instantaneous trip mechanism 600 is electrically connected to the fixed contact 430, one end of the arc extinguishing mechanism 700 is electrically connected to the fixed contact 430, and the other end of the arc extinguishing mechanism 700 is electrically connected to the delay trip mechanism 500.

Specifically, the first terminal 200 is used for being connected with an external conductor, a current output by the external conductor is output to the instantaneous trip mechanism 600 through the first terminal 200, the instantaneous trip mechanism 600 includes a short-circuit coil and a driving component, and when the current output to the short-circuit coil by the external conductor is greater than a threshold value of a protection current, the short-circuit coil generates enough electromagnetic force to drive the driving component to act, so as to control the switching component 400 to open, thereby realizing a short-circuit protection function of the circuit breaker 10.

Further, arc extinguishing mechanism 700 includes the metal arc chute piece that the polylith parallel interval set up and the insulation board of two parallel interval settings, and polylith metal arc chute piece is located between two insulation boards. When the moving contact 410 and the static contact 430 are separated, the generated electric arc enters the metal arc-extinguishing grid pieces through the static contact 430, and the electric arc is isolated by the multiple layers of the metal arc-extinguishing grid pieces, so that the energy of the electric arc is attenuated, and the purpose of arc extinguishing is achieved.

The above only is the preferred embodiment of the present invention, not limiting the scope of the present invention, all the equivalent structure changes made by the contents of the specification and the drawings under the inventive concept of the present invention, or the direct/indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A circuit breaker, characterized in that the circuit breaker comprises:

a housing;

the first wiring terminal, the second wiring terminal and the switch assembly are arranged in the shell, the first wiring terminal, the switch assembly and the second wiring terminal are electrically connected in sequence to form a main loop, and the switch assembly is used for controlling on/off of a power supply of the main loop; the switch component comprises a moving contact and a fixed contact, and a wiring part is convexly arranged on the moving contact; and

the time delay tripping mechanism is arranged in the shell, and the wiring part is electrically connected with the time delay tripping mechanism through a first lead; the wiring portion is further electrically connected with the second wiring end through a second conducting wire, and the fixed contact is electrically connected with the first wiring end.

2. The circuit breaker of claim 1, wherein the movable contact is disposed opposite to the fixed contact, the movable contact is disposed in the housing and is movable between an open position and a closed position, a first contact portion is disposed on a side of the movable contact facing the fixed contact, a second contact portion is disposed on the fixed contact corresponding to the first contact portion, and when the movable contact is in the closed position, the first contact portion abuts against and is in surface contact with the second contact portion.

3. The circuit breaker as claimed in claim 2, wherein a protrusion is disposed on a side of the movable contact facing the fixed contact, the first contact portion is disposed on the protrusion, a receiving groove is disposed on the movable contact corresponding to the protrusion, and the protrusion is fixedly mounted in the receiving groove.

4. The circuit breaker as claimed in claim 3, wherein the protrusion is fixed in the receiving groove by welding, a solder pad layer is formed by welding the protrusion and the movable contact, and a groove is formed on one side of the movable contact facing the protrusion or one side of the protrusion facing the movable contact, and the groove is used for receiving the solder pad layer.

5. The circuit breaker of claim 4, wherein a plurality of protrusions are disposed on a side of the protrusion facing the movable contact, the plurality of protrusions are sequentially spaced along a length direction of the protrusion, and the grooves are formed between adjacent protrusions.

6. The circuit breaker according to claim 1, wherein the time delay trip mechanism includes a first metal member and a second metal member, the connection portion is connected to the first metal member through the first wire, one end of the second metal member is connected to the first metal member, and the other end of the second metal member is connected to the second terminal.

7. The circuit breaker of claim 6, wherein the second metal member comprises a plurality of metal plates connected in series, wherein the plurality of metal plates are arranged in a meandering configuration.

8. The circuit breaker of claim 3, wherein the bump is made of a silver alloy material; and/or the thickness of the bump is larger than that of the movable contact.

9. The circuit breaker of claim 1, wherein the housing further comprises heat dissipation apertures.

10. The circuit breaker of claim 1, further comprising an instantaneous trip mechanism and an arc extinguishing mechanism, wherein one end of the instantaneous trip mechanism is electrically connected to the first terminal, the other end of the instantaneous trip mechanism is electrically connected to the stationary contact, one end of the arc extinguishing mechanism is electrically connected to the stationary contact, and the other end of the arc extinguishing mechanism is electrically connected to the delay trip mechanism.